Time-limit relay



H} H. w. HERBERS TIME LIMI'If- RELAY Filed Nov 13, 1924 INVENTOR Patented Oct. 4, 1927.

HERMANN H. W. EERBERS, OF EAST ORANGE, NEW JERSEY.

TIME-LIMIT RELAY.

Application filed November 13, 1924-. Serial No. 749,589.

This invention relates to a time limit relay device which may be used in connection with electric motors such as are used in driving large printing presses, whereby the motor may be caused to apply its maximum driving torque for a short period only when the driven mechanism is being started under way, the invention having for an object the provision of a novel and simple device that will automatically open the maximum-torque circuit to the motor after the elapse of" a predetermined time subsequent to the starting of the motor, so as to permit of further acceleration in the usual manner.

For further comprehension of the invention, and of the objects and advantages thereof, reference will be had to the following description and accompanying drawing, and to the appended claims in which the various novel features of the invention are more particularly set forth.

Fig. 1 of the drawing is a perspective view showing my improved relay mounted on a panel board. I

ig. 2 is a longitudinal sectional view of the shiftable circuit opening element.

Fig. 3 is a transverse sectional view thereof taken on the line 3-8 of Fig. 2.

Fig. 4 is a longitudinal sectional view tak en on a plane at right angles to Fig. 2 and along the line 4.-4 of the latter figure.

Fig. 5 is a transverse sectional view showing a slight modification.

' eferring now to the drawing, the reference numeral indicates a portion of an ordinary panel board having mounted there on the usual switches and other parts having to do with the control of the electric motor. Upon this panel board an electro-magnet 12 is mounted. The armature of this magnet comprises an arm 14 fixed on a horizontal shaft 15 supported by suitable bearing elements 16 on the panel board. This shaft 15 has also fixed thereon a contact arm 17 that is adapted to engage a contact 18 mount ed on the panel board when the shaft 15 is rocked by the attraction of the armature 14. of the magnet 12.

hen the magnet is energized upon starting of the motor, and the shaft 15 is rocked, my improved time limit relay is set to operate in a given length of time, three seconds for My improved relay comprises a receptacle or vessel 20 which is preferably constructed of glass and which consists of a pair of bulbs instance, after the starting of the motor.

20 and 20 connected by a narrow neck 20, that may be longitudinally curved or may be straight. This vessel is mounted on the up per end of a short arm 22 that is fixed on one end of a rock shaft 23, the upper end of this arm gripping the neck 20". The rock shaft 28 is mounted in a bearing bracket-'24 fixed to and projecting from the panel board 10, and has a crank 25 on its other end having a tip 26 projected from its free end parallel to the shaft 23. This tip 26 engages in a longitudinal slot 27 in the upper end of another arm 28 fixed on the shaft 15 Fixed in the side of the bulb 20, and projecting into the interior thereof, are a pair of contact points 30 that are Wired, when the invention is applied to a motor, into the maximum torque circuit of the motor, the said contact points being located adjacent the bottom of the bulb. A quantity of mercury is placed in the vessel 20, the quantity being considerably less than the total capacity of the'vessel and being calculated so that a sufficient amount may flow from the bulb 20 to expose the contacts 30 in thedesired length of time. To permit of passage of air from one bulb to the other bulbs are connected by a bypass tube 32 that leads from the top of one to the top of the other. This bypass tube has an opening therein for the insertion of mercury in the vessel, this opening being surrounded by the flange 33. lf desired the vessel 20 might be sealed and the space above the mercury filled with a neutral gas to prevent oxidation of the mercury by the spark; or it might be made simpler by eliminating the tube and exhausting the air over the mercury. In Fig. 5 of the drawing I have indicated an arrangement permitting of ready variation of the time in which the relay operates. As here shown the neck 20 is formed with a small opening 35 while the collar 22 of the arm 22 that encircles the neck has a screw threaded thereinto, and which may e projected by varying distances into the said neck to increase or diminish the size of the passage therethrough.

When the motor is not runnin the vessel 20 remains at an opposite inclination from that shown, with the bulb 20 elevated instead of the bulb 20, the mercury in the vessel being then collected in the bulb 20.

W hen the motor is started and the magnet 12 energized, the shaft 15 is rocked, causing the shaft 23 to be likewise rocked by the arm.

28. The vessel 20 is thus shifted to the pogaginga rock shaft sition shown in the drawing, with the bulb 20 elevated. 'lhe mercury in the said bulb bridges the two contacts as will be understood, and circuit in which the two contacts 30 are placed is closed for such length of time as it is required for the mercury to run from the bulb 20 and leave the contacts 30 exposed.

It will be understood of course that the.

operation might be reversed to close a cirof said contact arm adapted to be engaged.

bythe latter when said shaft is rotated, an arm provided with a longitudinal slot en- 7 supported by a bearing bracket on said panel, said rock shaft provided with an arm fastened to a tiltable mercury-containing vessel presenting a pair of chambers connected by a narrow passage, one of said chambers provided with contact members, whereby said vessel is shifted to elevate the said chamber when the said horizontal shaft is rocked by energizing of said magnet to, cause the mercury to flow from said elevated chamber and away from said contact members for opening the electric circuit therebetween after said contact arm and the contact on saidpa-nels have been in engagement a predetermined period of time.

2. The combination in a device of the class described having a panel board provided with bearing elements supporting a horizontal shaft having rigidly attached thereto, an armature arm cosactable with an electroinagnet mounted on said, panel, a' contact arm mounted on said shaft adapted to engage a contact on said panel. when said horizontal shaft is rotated by excitation of said magnet, an arm provided with a longitudinal slot engaging a rock, shaft supported by a bearing bracket on said panel, said rock shaft provided with an arm fastened to a tiltable mercury-containing vessel presenting a pair or" chambers connected by a narrowpassage having an. adjustable member projecting therein to. permit of variation of the area of said passage, one, of said chambers'provided with contact members, Whereby said vessel is shifted to elevate the said chamber when the said horizontal shaft is rocked by energizing of said magnet to cause mercury to How from said elevated chamber to open the electric circuit between said enclosed contactsafter said contact" arm has been in engagement with the. contact ofsaid panel board for a predetermined period of time.

In testimony whereof I have affixed my signature.

HERMANN- H. W. HERBERS. 

